The objective of the present invention is to provide a simplified and reliable hydrometer unit for permanent installation directly in an engine coolant line, such as an automobile heater hose, whereby a direct visual indication of anti-freeze strength or weakness in the liquid coolant is obtainable at any time without the necessity for manipulating or even touching the hydrometer unit.
A further object of the invention is to provide a coolant line hydrometer of inexpensive construction which utilizes specific gravity of the coolant to provide a direct visual indication of coolant strength or weakness. A plurality of variously colored float elements contained within a coolant receiving chamber of the hydrometer are individually formulated to float and position themselves adjacent to a transparent viewing portion of the hydrometer to indicate the condition or strength of the anti-freeze component of the coolant, based on its specific gravity at any given time. If no float elements are viewable, the anti-freeze strength is inadequate. If a single float element is viewable, the anti-freeze strength is somewhat greater but may still be inadequate. If two or more float elements are viewable, an increasing anti-freeze strength is visually indicated.
A further feature of the invention is that the coolant line hydrometer unit can be used to drain liquid coolant from the system and additional anti-freeze can be added to the system through the hydrometer unit. Also, the device can be employed with a garden hose to flush out the coolant system after opening the drain at the bottom of the engine radiator.
Other features and advantages of the invention will become apparent during the course of the following description.